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Finding the Fourth Proportional to 686.75, 1,029.45 and 378.30

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Solution

The fourth proportional to 686.75, 1,029.45 and 378.30 is: 567.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.75 : 1,029.45 = 378.30 : x
  2. Step 2: Convert to fraction form
    686.75/1,029.45 = 378.30/x
  3. Step 3: Cross multiply
    686.75x = 1,029.45 × 378.30
  4. Step 4: Simplify right side
    686.75x = 389,440.94
  5. Step 5: Solve for x
    x = 389,440.94/686.75
  6. Step 6: Final answer
    x = 567.08

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.